1. Field of the Invention
This invention relates to a process of dressing a refractory structure. The invention also relates to a particulate composition suitable for use in a process of dressing a refractory structure.
While processes according to the present invention may be used for various purposes, they are of particular value as a stage in the repair of damaged refractory structures.
2. Description of the Related Art
Refractory structures of various types, such as metallurgical furnaces, coke ovens and glass melting furnaces tend to become damaged during the course of their working lives.
Such damage may for example be manifest as slippage of one or more refractory blocks in relation to the main structure which results in an irregular surface profile, or as cracking of the refractory structure. It is in general desirable to re-establish the designed surface profile of the refractory structure, and it is also desirable to prevent further slippage of the block(s) in question and to fill any gap left by its or their displacement or cracking. In order to achieve these ends, it may be necessary or desirable to cut away any protruding portion of the refractory structure. Alternatively or in addition it may be necessary or desirable to cut a keyway into a slipped block and/or a neighbouring block so that a key may be formed in or inserted into the keyway to prevent further slippage. Alternatively or in addition, it may be necessary or desirable to enlarge or shape any gap left by such slippage or cracking for the formation or insertion of a suitable plug.
Such damage may alternatively be due to erosion of the material of the refractory structure. Such erosion tends to impart an irregular surface profile to the structure and it is often desirable to modify that surface profile before effecting a repair to the structure.
It may be necessary or desirable to form a hole in or otherwise dress a refractory structure for other purposes.
A refractory structure could of course be dressed mechanically, for example using a cutting wheel, drill or other tool, but this presents certain disadvantages for refractory repair. In order to dress the refractory and leave a surface suitable for repair, the operator would usually have to approach the dressing site quite closely, and this implies that that site would have to be at a temperature which the operator could tolerate for the time necessary to effect the dressing. This in turn implies that the refractory structure would have to be cooled from its normal operating temperature, or a temperature which is within its normal working cycle of operating temperatures. And it would have to be reheated after dressing and repair. In the case of industrial furnaces of various types, in order to avoid damage to the furnace as its refractory material contracts or expands, such cooling and reheating might have to be scheduled over a period of several days or even a few weeks, and this would accordingly represent a considerable loss in production from that furnace.